Oh it's a business strategy alright, and yes, the crux of the issue is money.
MS wants everybody using Windows 10!
MS 'looses' piles and piles of money every year offering support to 7 different operating systems, on 'umpteen' different devices, in who knows how many different languages in whatever countries for 'X' number of years to come......
... and that's just the beginning!
However, in reality, there isn't any "license police" that will prevent you from going back and installing your retail copy on a different computer if your first one died. I think most people would consider this "fair game", even if the letter of the license may not.
You could then upgrade to Windows 10 on the new computer. In reality, there is talk of MS allowing "non-genuine" copies of Windows to upgrade to Windows 10 for free as well anyways, so the point may well be moot.
The key is that you can't upgrade your copy of Windows 7, then install that copy of Windows 7 on a new computer, leaving Windows 10 on the old one. You would have to not be able to use Windows 10 on the old one.
I'm not suggesting Microsoft is doing this out of the goodness of their heart. But the fact is, you're getting it for free. And there is no requirement that you buy anything else (certainly MS hopes you will, but you don't have to). To complain because they aren't giving you a totally unencumbered copy you can transfer to any PC for all eternity is just being greedy in my book.
Microsoft should just clarify everything about the upgrade soon.
Did it ever occur to you that Microsoft has recognized the damage created by Windows 8 (8.1 is measurably better and I have learned to like it) and is using this offering to somewhat repair its image? Kinda like saying, "I'm sorry," without saying it in so many words. Stranger things have happened.
Finally, your accusations don't hold water.
I'm not looking a gift horse in the mouth, I'm making sure that the horse is not a trojan, and calling fault for potential underhanded representation of the gift - which I believe is wrong towards those who will be stuck by it, and I think that most people cannot be expected to have invested time into understanding MS' reasoning behind the upgrade offer ( forum-discussions and their produced comprehensions do not represent the understanding of an average PC user, who is far more likely to take an upgrade offer at its overly-simplistic face value ).
Once Windows 10 is released and its upgrade accepted, the time for scrutiny is over. If it releases and everything is great, then MS will be worthy of praise. Before then, praise is based on nothing but an insisted sentiment, and it might backfire down the road - and I think that without scrutiny, it will.
From the Manufacturer
"Use of this OEM System Builder Channel software is subject to the terms of the Microsoft OEM System Builder License. This software is intended for pre-installation on a new personal computer for resale. This OEM System Builder Channel software requires the assembler to provide end user support for the Windows software and cannot be transferred to another computer once it is installed. To acquire Windows software with support provided by Microsoft please see our full package "Retail" product offerings."